Sustaining Terrestrial Biodiversity: The Ecosystem Approach Chapter 10

Core Case Study: Reintroducing Gray Wolves to Yellowstone Around 1800 1850–1900: decline due to human activity U.S. Endangered Species Act: 1973 1995–1996: relocation of gray wolves to Yellowstone Park 2008: Gray wolf no longer protected

Natural Capital Restoration: the Gray Wolf

10-1 What Are the Major Threats to Forest Ecosystems? (1) Concept 10-1A Forest ecosystems provide ecological services far greater in value than the value of raw materials obtained from forests. Concept 10-1B Unsustainable cutting and burning of forests, along with diseases and insects, are the chief threats to forest ecosystems.

10-1 What Are the Major Threats to Forest Ecosystems? (2) Concept 10-1C Tropical deforestation is a potentially catastrophic problem because of the vital ecological services at risk, the high rate of tropical deforestation, and its growing contribution to global warming.

Forests Vary in Their Make-Up, Age, and Origins Old-growth or primary forest 36% of world’s forests Second-growth forest 60% of world’s forests Tree plantation, tree farm or commercial forest 4% of world’s forests May supply most of the industrial wood in the future

Natural Capital: An Old-Growth Forest and an Old-Growth Tropical Forest

Rotation Cycle of Cutting and Regrowth of a Monoculture Tree Plantation

Figure 10.3 Short (25- to 30-year) rotation cycle of cutting and regrowth of a monoculture tree plantation used in modern industrial forestry. In tropical countries, where trees can grow more rapidly year-round, the rotation cycle can be 6–10 years. Old-growth or second-growth forests are clear-cut to provide land for growing most tree plantations (see photo, right). Question: What are two ways in which this process can degrade an ecosystem? Fig. 10-3a, p. 216

Weak trees removed 25 yrs Clear cut 30 yrs 15 yrs Years of growth Figure 10.3 Short (25- to 30-year) rotation cycle of cutting and regrowth of a monoculture tree plantation used in modern industrial forestry. In tropical countries, where trees can grow more rapidly year-round, the rotation cycle can be 6–10 years. Old-growth or second-growth forests are clear-cut to provide land for growing most tree plantations (see photo, right). Question: What are two ways in which this process can degrade an ecosystem? Seedlings planted 5 yrs 10 yrs Fig. 10-3a, p. 216

Figure 10.3 Short (25- to 30-year) rotation cycle of cutting and regrowth of a monoculture tree plantation used in modern industrial forestry. In tropical countries, where trees can grow more rapidly year-round, the rotation cycle can be 6–10 years. Old-growth or second-growth forests are clear-cut to provide land for growing most tree plantations (see photo, right). Question: What are two ways in which this process can degrade an ecosystem? Fig. 10-3b, p. 216

Forests Provide Important Economic and Ecological Services (1) Support energy flow and chemical cycling Reduce soil erosion Absorb and release water Purify water and air Influence local and regional climate Store atmospheric carbon Habitats

Forests Provide Important Economic and Ecological Services (2) Wood for fuel Lumber Pulp to make paper Mining Livestock grazing Recreation Employment

Natural Capital: Major Ecological and Economic Services Provided by Forests

Science Focus: Putting a Price Tag on Nature’s Ecological Services Forests valued for ecological services Nutrient cycling Climate regulation Erosion control Waste treatment Recreation Raw materials $4.7 Trillion per year

Estimated Annual Global Economic Values of Ecological Services Provided by Forests

Worth (billions of dollars) 400 350 300 250 200 Worth (billions of dollars) 150 100 50 Figure 10.A Estimated annual global economic values of some ecological services provided by forests compared to the raw materials they produce (in billions of dollars). Nutrient cycling Climate regulation Erosion control Waste treatment Recreation Raw materials Ecological service Fig. 10-A, p. 218

Unsustainable Logging is a Major Threat to Forest Ecosystems (1) Increased erosion Sediment runoff into waterways Habitat fragmentation Loss of biodiversity

Unsustainable Logging is a Major Threat to Forest Ecosystems (2) Invasion by Nonnative pests Disease Wildlife species Major tree harvesting methods: Selective cutting Clear-cutting Strip cutting

Natural Capital Degradation: Building Roads into Previously Inaccessible Forests

Cleared plots for grazing New highway Highway Cleared plots for agriculture Old growth Figure 10.5 Natural capital degradation: Building roads into previously inaccessible forests paves the way to fragmentation, destruction, and degradation. Fig. 10-5, p. 218

Major Tree Harvesting Methods

Figure 10.6 Major tree harvesting methods. Question: If you were cutting trees in a forest you owned, which method would you choose and why? Fig. 10-6a, p. 219

(a) Selective cutting Clear stream Figure 10.6 Major tree harvesting methods. Question: If you were cutting trees in a forest you owned, which method would you choose and why? Clear stream Fig. 10-6a, p. 219

Figure 10.6 Major tree harvesting methods. Question: If you were cutting trees in a forest you owned, which method would you choose and why? Fig. 10-6b, p. 219

(b) Clear-cutting Muddy stream Figure 10.6 Major tree harvesting methods. Question: If you were cutting trees in a forest you owned, which method would you choose and why? Muddy stream Fig. 10-6b, p. 219

Figure 10.6 Major tree harvesting methods. Question: If you were cutting trees in a forest you owned, which method would you choose and why? Fig. 10-6c, p. 219

(c) Strip cutting Uncut Cut 1 year ago Dirt road Cut 3–10 years ago Figure 10.6 Major tree harvesting methods. Question: If you were cutting trees in a forest you owned, which method would you choose and why? Clear stream Fig. 10-6c, p. 219

(a) Selective cutting (c) Strip cutting Clear stream (b) Clear-cutting Muddy stream Uncut Cut 1 year ago Dirt road Cut 3–10 years ago Clear stream Figure 10.6 Major tree harvesting methods. Question: If you were cutting trees in a forest you owned, which method would you choose and why? Stepped Art Fig. 10-6a, p. 219

Clear-Cut Logging in Washington State, U.S.

Trade-offs: Advantages and Disadvantages of Clear-Cutting Forests

TRADE-OFFS Clear-Cutting Forests Advantages Disadvantages Higher timber yields Reduces biodiversity Destroys and fragments wildlife habitats Maximum profits in shortest time Figure 10.8 Advantages and disadvantages of clear-cutting forests. Question: Which single advantage and which single disadvantage do you think are the most important? Why? Can reforest with fast-growing trees Increases water pollution, flooding, and erosion on steep slopes Good for tree species needing full or moderate sunlight Eliminates most recreational value Fig. 10-8, p. 220

Fire, Insects, and Climate Change Can Threaten Forest Ecosystems (1) Surface fires Usually burn leaf litter and undergrowth May provide food in the form of vegetation that sprouts after fire Crown fires Extremely hot: burns whole trees Kill wildlife Increase soil erosion

Fire, Insects, and Climate Change Can Threaten Forest Ecosystems (2) Introduction of foreign diseases and insects Accidental Deliberate Global warming Rising temperatures Trees more susceptible to diseases and pests Drier forests: more fires More greenhouse gases

Surface and Crown Fires

U.S. Forest Invading Nonnative Insect Species and Disease Organisms

White pine blister rust Pine shoot beetle Beech bark disease Figure 10.10 Natural capital degradation: some of the nonnative insect species and disease organisms that have invaded U.S. forests and are causing billions of dollars in damages and tree loss. The light green and orange colors in the map show areas where green or red overlap with yellow. (Data from U.S. Forest Service) Sudden oak death Hemlock woolly adelgid Fig. 10-10, p. 221

We Have Cut Down Almost Half of the World’s Forests Deforestation Tropical forests Especially in Latin America, Indonesia, and Africa Boreal forests Especially in Alaska, Canada, Scandinavia, and Russia

Natural Capital Degradation: Extreme Tropical Deforestation in Thailand

Natural Capital Degradation: Harmful Environmental Effects of Deforestation

Case Study: Many Cleared Forests in the United States Have Grown Back Forests of the eastern United States decimated between 1620 and 1920 Grown back naturally through secondary ecological succession Biologically simplified tree plantations reduce biodiversity

Tropical Forests are Disappearing Rapidly Majority of loss since 1950 Brazil and Indonesia tropical forest loss Role of deforestation in species’ extinction

Satellite Images of Amazon Deforestation between 1975 and 2001

Species Diversity

Causes of Tropical Deforestation Are Varied and Complex Primary Secondary

Major Causes of the Destruction and Degradation of Tropical Forests

NATURAL CAPITAL DEGRADATION Major Causes of the Destruction and Degradation of Tropical Forests Basic Causes Secondary Causes • Not valuing ecological services • Roads • Cattle ranching • Crop and timber exports • Fires • Logging • Settler farming • Tree plantations • Government policies • Cash crops • Poverty • Population growth Cattle ranching Tree plantations Logging Cash crops Figure 10.15 Major interconnected causes of the destruction and degradation of tropical forests. The importance of specific secondary causes varies in different parts of the world. Question: If we could eliminate the basic causes, which if any of the secondary causes might automatically be eliminated? Settler farming Fires Roads Fig. 10-15, p. 225

NATURAL CAPITAL DEGRADATION • Not valuing ecological services • Government policies • Poverty • Population growth NATURAL CAPITAL DEGRADATION Major Causes of the Destruction and Degradation of Tropical Forests Basic Causes • Crop and timber exports Cattle ranching Tree plantations Logging Cash crops Settler farming Fires Roads Secondary Causes • Roads • Cattle ranching • Fires • Logging • Settler farming • Tree plantations • Cash crops Figure 10.15 Major interconnected causes of the destruction and degradation of tropical forests. The importance of specific secondary causes varies in different parts of the world. Question: If we could eliminate the basic causes, which if any of the secondary causes might automatically be eliminated? Stepped Art Fig. 10-15, p. 225

Natural Capital Degradation: Large Areas of Brazil’s Amazon Basin Are Burned

Animation: Hubbard Brook experiment

Video: Forest fire

10-2 How Should We Manage and Sustain Forests? Concept 10-2 We can sustain forests by emphasizing the economic value of their ecological services, protecting old-growth forests, harvesting trees no faster than they are replenished, and using sustainable substitute resources.

Solution: Sustainable Forestry

We Can Improve the Management of Forest Fires (1) The Smokey Bear educational campaign Prescribed fires Allow fires on public lands to burn Protect structures in fire-prone areas Thin forests in fire-prone areas

We Can Improve the Management of Forest Fires (2) 2003 Healthy Forests Restoration Act Pros Cons

Science Focus: Certifying Sustainably Grown Timber Collins Pine Owns and manages protective timberland Forest Stewardship Council Nonprofit Developed list of environmentally sound practices Certifies timber and products

We Can Reduce the Demand for Harvested Trees Improve the efficiency of wood use Make tree-free paper Kenaf Hemp

Solutions: Fast-Growing Plant: Kenaf

Case Study: Deforestation and the Fuelwood Crisis Possible solutions Establish small plantations of fast-growing fuelwood trees and shrubs Burn wood more efficiently Solar or wind-generated electricity Haiti: ecological disaster South Korea: model for successful reforestation

Governments and Individuals Can Act to Reduce Tropical Deforestation Reduce fuelwood demand Practice small-scale sustainable agriculture and forestry in tropical forest Debt-for-nature swaps Conservation concessions Use gentler logging methods Buy certified lumber and wood products

Individuals Matter: Wangari Maathari and Kenya’s Green Belt Movement Self-help group of women in Kenya Success of tree planting Nobel Peace Prize: 2004

Solutions: Sustaining Tropical Forests

SOLUTIONS Sustaining Tropical Forests Prevention Restoration Protect the most diverse and endangered areas Encourage regrowth through secondary succession Educate settlers about sustainable agriculture and forestry Subsidize only sustainable forest use Rehabilitate degraded areas Protect forests with debt-for-nature swaps and conservation concessions Figure 10.19 Ways to protect tropical forests and use them more sustainably (Concept 10-2). Question: Which three of these solutions do you think are the most important? Why? Certify sustainably grown timber Concentrate farming and ranching in already-cleared areas Reduce poverty Slow population growth Fig. 10-19, p. 231

10-3 How Should We Manage and Sustain Grasslands? Concept 10-3 We can sustain the productivity of grasslands by controlling the number and distribution of grazing livestock and restoring degraded grasslands.

Some Rangelands Are Overgrazed (1) Important ecological services of grasslands Soil formation Erosion control Nutrient cycling Storage of atmospheric carbon dioxide in biomass Maintenance of diversity

Some Rangelands are Overgrazed (2) Overgrazing of rangelands Reduces grass cover Leads to erosion of soil by water and wind Soil becomes compacted Enhances invasion of plant species that cattle won’t eat Malapi Borderlands Management success story

Natural Capital Degradation: Overgrazed and Lightly Grazed Rangeland

We Can Manage Rangelands More Sustainably (1) Rotational grazing Suppress growth of invasive species Herbicides Mechanical removal Controlled burning Controlled short-term trampling

We Can Manage Rangelands More Sustainably (2) Replant barren areas Apply fertilizer Reduce soil erosion

Case Study: Grazing and Urban Development the American West American southwest: population surge since 1980 Land trust groups: limit land development Reduce the harmful environmental impact of herds Rotate cattle away from riparian areas Use less fertilizers and pesticides Operate ranch more economically

Restoration of Grazing Lands

10-4 How Should We Manage and Sustain Parks and Natural Reserves? Concept 10-4 Sustaining biodiversity will require protecting much more of the earth’s remaining undisturbed land area as parks and nature reserves.

National Parks Face Many Environmental Threats Worldwide: 1100 major national parks Parks in developing countries Greatest biodiversity 1% protected against Illegal animal poaching Illegal logging and mining

Case Study: Stresses on U.S. Public Parks 58 Major national parks in the U.S. Biggest problem may be popularity Noise Congestion Pollution Damage or destruction to vegetation and wildlife Repairs needed to trails and buildings

Natural Capital Degradation: Damage From Off-Road Vehicles

Solutions: National Parks

Science Focus: Effects of Reintroducing the Gray Wolf to Yellowstone National Park Gray wolves prey on elk and push them to a higher elevation Regrowth of aspen, cottonwoods, and willows Increased population of riparian songbirds Reduced the number of coyotes Fewer attacks on cattle Wolf pups susceptible to parvovirus carried by dogs

Nature Reserves Occupy Only a Small Part of the Earth’s Land Conservationists’ goal: protect 20% of the earth’s land Cooperation between government and private groups Nature Conservancy Eco-philanthropists Developers and resource extractors opposition

Designing and Connecting Nature Reserves Large versus small reserves The buffer zone concept United Nations: 529 biosphere reserves in 105 countries Habitat corridors between isolated reserves Advantages Disadvantages

Solutions: A Model Biosphere Reserve

Visitor education center Biosphere Reserve Core area Research station Visitor education center Figure 10.24 Solutions: a model biosphere reserve. Each reserve contains a protected inner core surrounded by two buffer zones that local and indigenous people can use for sustainable logging, growing limited crops, grazing cattle, hunting, fishing, and ecotourism. Question: Do you think some of these reserves should be free of all human activity, including ecotourism? Why or why not? Buffer zone 1 Human settlements Buffer zone 2 Fig. 10-24, p. 237

Case Study: Costa Rica—A Global Conservation Leader 1963–1983: cleared much of the forest 1986–2006: forests grew from 26% to 51% Goal: to reduce net carbon dioxide emissions to zero by 2021 Eight zoned megareserves Designed to sustain around 80% of Costa Rica’s biodiversity

Solutions: Costa Rica: Parks and Reserves—Megareserves

Nicaragua Caribbean Sea Costa Rica Panama Pacific Ocean Figure 10.25 Solutions: Costa Rica has consolidated its parks and reserves into eight zoned megareserves designed to sustain about 80% of the country’s rich biodiversity. Green areas are protected reserves and yellow areas are nearby buffer zones, which can be used for sustainable forms of forestry, agriculture, hydropower, hunting, and other human activities. Pacific Ocean National parkland Buffer zone Fig. 10-25, p. 238

Protecting Wilderness Is an Important Way to Preserve Biodiversity Pros Cons

Case Study: Controversy over Wilderness Protection in the United States Wilderness Act of 1964 How much of the United States is protected land? Roadless Rule 2005: end of roadless areas within the national forest system

Video: Wolf pack

10-5 What is the Ecosystem Approach to Sustaining Biodiversity? (1) Concept 10-5A We can help sustain biodiversity by identifying severely threatened areas and protecting those with high plant diversity and those where ecosystem services are being impaired. Concept 10-5B Sustaining biodiversity will require a global effort to rehabilitate and restore damaged ecosystems.

10-5 What is the Ecosystem Approach to Sustaining Biodiversity? (2) Concept 10-5C Humans dominate most of the earth’s land, and preserving biodiversity will require sharing as much of it as possible with other species.

We Can Use a Four-Point Strategy to Protect Ecosystems Map global ecosystems; identify species Locate and protect most endangered species Restore degraded ecosystems Development must be biodiversity-friendly Are new laws needed?

Protecting Global Biodiversity Hot Spots Is an Urgent Priority 1988: Norman Myers Identify biodiversity hot spots rich in plant species Not sufficient public support and funding Drawbacks of this approach May not be rich in animal diversity People may be displaced and/or lose access to important resources

Endangered Natural Capital: 34 Biodiversity Hotspots

Endangered Natural Capital: Biodiversity Hotspots in the U.S.

3 Southern Appalachians Top Six Hotspots 1 Hawaii 2 San Francisco Bay area 3 Southern Appalachians 4 Death Valley 5 Southern California 6 Florida Panhandle Figure 10.27 Endangered natural capital: biodiversity hotspots in the United States that need emergency protection. The shaded areas contain the largest concentrations of rare and potentially endangered species. Compare these areas with those on the map of the human ecological footprint in North America shown in Figure 7, pp. S28–S29, in Supplement 4. Question: Do you think that hotspots near urban areas would be harder to protect than those in rural areas? Explain. (Data from State Natural Heritage Programs, The Nature Conservancy, and Association for Biodiversity Information) Concentration of rare species Low Moderate High Fig. 10-27, p. 241

Case Study: A Biodiversity Hot Spot in East Africa Eastern Arc Mountains of Tanzania, Africa Highest concentration of endangered species on earth Threatened due to Killing of forests by farmers and loggers Hunting Fires

Protecting Ecosystem Services Is Also an Urgent Priority U.N. Millennium Ecosystem Assessment: 2005 Identify key ecosystem services Human activities degrade or overuse 62% of the earth’s natural services Identify highly stressed life raft ecosystems

We Can Rehabilitate and Restore Ecosystems That We Have Damaged (1) Study how natural ecosystems recover Restoration Rehabilitation Replacement Creating artificial ecosystems

We Can Rehabilitate and Restore Ecosystems That We Have Damaged (2) How to carry out most forms of ecological restoration and rehabilitation Identify what caused the degradation Stop the abuse Reintroduce species, if possible Protect from further degradation

Science Focus: Ecological Restoration of a Tropical Dry Forest in Costa Rica Guanacaste National Park restoration project Relinked to adjacent rain forest Bring in cattle and horses – aid in seed dispersal Local residents – actively involved

Solutions: Curtis Prairie in Madison, WI (U.S.)

Will Restoration Encourage Further Destruction? Preventing ecosystem damage is cheaper than restoration About 5% of the earth’s land is preserved from the effects of human activities

We Can Share Areas We Dominate With Other Species Win-Win Ecology: How Earth’s Species Can Survive in the Midst of Human Enterprise, by Michael L. Rozenweig, 2003 Reconciliation or applied ecology Community-based conservation Belize and the black howler monkeys Protect vital insect pollinators Bluebird protection with special housing boxes Berlin, Germany: rooftop gardens San Francisco: Golden Gate Park

Case Study: The Blackfoot Challenge—Reconciliation Ecology in Action 1970s: Blackfoot River Valley in Montana threatened by Poor mining, logging, and grazing practices Water and air pollution Unsustainable commercial and residential development Community meetings led to Weed-pulling parties Nesting structures for waterfowl Developed sustainable grazing systems

What Can You Do? Sustaining Terrestrial Biodiversity

Active Figure: Biodiversity hot spots